The subject matter herein relates to a railway car truck and, more particularly, to a railway car truck having an improved brake beam wear liner.
In a railway car truck, two axles are held in a pair of laterally spaced side frames, with a bolster extending laterally between and supported on each side frame. The wheels are press fit on the axles, with the ends of the axles also fitted with a roller bearing assembly. The roller bearing assembly is fit into a bearing adapter that is fit into a pedestal jaw opening at the longitudinal end of each side frame.
Each railway car truck also includes a braking system having two brake beams that act to transmit braking force through brake shoes to the outer tread of the railway wheels. The brake beams are attached to the side frames in corresponding guide brackets (AAR standard S-366, 2006 revision). For example, ends of the brake beams are received in the guide brackets. The brake beams are movable within the guide brackets during application of the braking system. Typically, wear plates (AAR standard S-367, 1997 revision) are positioned within the guide brackets. The wear plates have a base wall, opposed sidewalls and flanges extending from the ends of the sidewalls opposite the base wall.
During operation, the side frames tend to shift with respect to one another, such as when the railway car truck is going around a bend, or when the load supported by the railway car truck shifts or changes. The side frames may tend to shift inboard, which could squeeze in on the brake beam. As such, the brake beam is typically sized to create a gap or tolerance between the wear plates to avoid binding of the brake beams. However, such gap may be too wide in some situations, such as when the side frames are shifted outboard, when the brake beam is off-center or kinked out of alignment, or when the brake beam used is undersized for the particular rail gauge. When the gap is too wide, the brake beam is allowed to migrate within the pockets of the guide brackets, which could lead to damage of the railway wheels. For example, when the brake beam shifts over to one side or the other, the brake shoe and/or the brake head holding the brake shoe may begin to rub on the flange of the railway wheel, causing damage and/or failure of the railway wheel. Furthermore, the problem with brake beam shift may be exaggerated on particular types of railway cars, such as hopper cars, where the lever actuating the brake beam is angled to one side. As the brake beam is pulled to the side, the brake shoe and/or the brake head are similarly pulled toward the flange of the railway wheel.
A need exists for an improved railway car truck having a brake beam wear liner that can compensate for conditions where the brake beam is off-center during a braking condition.